In the modern times, a digital radio system has become one of essential techniques due to its reliability and the fact that a radio band can be used efficiently.
In recent years, along with the spread of the Internet, there is an increasing demand for high-speed, large-capacity communications using a wireless medium. Therefore, a radio communication system using a radio communication apparatus such as a radio repeater for P-to-P (point-to-point) connection of LANs (Local Area Networks) of the bases of separate buildings or the like has been developed and put into practical use.
In the radio communication system for P-to-P (point-to-point) communications, carriers in a millimeter wave band and a quasi-millimeter wave band having a short wavelength and high directivity may be used. In this case, it is required to secure a “view” in which an obstacle is not present between one radio communication apparatus and the other radio communication apparatus.
However, even if it was appropriate when installing the radio communication system, a failure may occur in the radio communications due to various factors as the system continuously operates for a long time.
For example, the radio communication system for P-to-P (point-to-point) communications is installed and used after being moved freely unlike the authorized fixed station. Accordingly, there is no protection of a propagation path by law, and the communications may not be performed due to an obstacle in the propagation path. That is, if a building is newly built in the radio propagation path or a tree grows to block the propagation path, the radio may be disconnected.
In addition, since there is directivity of the carriers in the millimeter wave band and the quasi-millimeter wave band, in rare cases, the direction may be shifted due to strong wind and an impact, which is resulted in a failure of the radio communications.
For example, Patent Document 1 describes a radio communication device characterized in that a camera is embedded in a radio device for fixed communications, and the direction of the radio device for fixed communications is changed to display an opponent radio communication station in a specific range of the monitor screen of the camera (hereinafter, referred to as Related Art 1).
Further, e.g., Patent Document 2 describes a radio communication system including at least two antennas, a radio unit for performing radio communications with an opposing radio device through the two antennas, and a control unit for controlling the switching of transmission and reception of the two antennas, the control unit switching the transmission and reception of the two antennas by receiving a predetermined timing signal (hereinafter, referred to as Related Art 2).
Patent Document 1: Japanese Patent Application Publication No. 2005-072780
Patent Document 2: Japanese Patent Application Publication No. 2011-176561
In the conventional radio communication system, when a failure occurs in the radio communications, in an important radio line, it was necessary to restore the system by determining the cause quickly.
However, in the conventional radio communication system, monitoring is performed only by measuring a S/N ratio or reception level. Thus, in order to discover the true cause of the failure such as construction of the building, there is a problem that it is necessary for an operator to go to the installation location of the radio communication device and perform a checking operation. Therefore, in the case where the radio device is installed in a distant area or place where the operator cannot easily access, it takes time to identify and recover the failure.
However, in the device described in Related Art 1, it was able to only see the image for adjusting the direction of the antenna. Thus, it was impossible to estimate the cause of the failure of the radio communications during the operation, or know whether the radio wave condition is likely to become worse afterwards. Further, Related Art 2 fails to disclose a technique of estimating the cause of a failure of the radio communications.